BirdAnalyst
Species · Colorado · BBS 2026 Release · 1966–2025

Green-winged Teal Population Trend in Colorado

All statesWaterfowl

Green-winged Teal in Colorado has declined: down 42% on the route-weighted index since 1973.

-42%Since 1973TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
72Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Green-winged Teal Trends in ColoradoNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Green-winged Teal in Colorado. See the full index history below.

Green-winged Teal Population Forecast in Colorado

If the recent trend holds, Green-winged Teal in Colorado is projected to stay roughly flat through 2030, near 0.22 (95% range 0.00–0.56). A 5-year backtest shows a typical error of ±85.8%, with 100% of held-out values landing inside the 95% band.

-8%Change by 2030TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.22Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.5695% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±85.8%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Green-winged Teal in Colorado is projected to stay roughly flat through 2030, near 0.22 (95% range 0.00–0.56). A 5-year backtest shows a typical error of ±85.8%, with 100% of held-out values landing inside the 95% band.19692030
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20260.230.000.57
20270.230.000.57
20280.230.000.56
20290.220.000.56
20300.220.000.56

Green-winged Teal Survey Routes in Colorado

Routes recording Green-winged Teal in Colorado.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Haswell1920221994
Cortez 21220152015
Karval1220142014
Lay1120252000
Fleming820031973
South Fork620251994
Briggsdale520232023
Walden520171991
Wildhorse L520241988
Mosca519971993
Yellowjacket Pass420252014
Last Chance319941976
Lamar319791979
Nunn320172002
Weston Pass320001999
Dunckley Pas320111992
De Beque320032003
Groundhog Rs320041994
Angora320052005
Rifle Falls319991999
Maybell219931989
Arsenal219981998
Douglas Pass220241991
Delta219841975
Colona220051973

Green-winged Teal Population Trend in Other States

alaskaarizonacaliforniaidahoillinoisindianaiowakansasmainemichiganminnesotamissourimontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-dakotaoklahomaoregonpennsylvaniasouth-dakotatexasutahvermontwashingtonwisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.